As initial excitement faded, shares of the Menlo Park, California-based company were trading flat at $4.17 after rising 12 percent to $4.68 on Wednesday morning on Nasdaq.

“You are talking about a company that has been anticipating the data for some time and the buying rate was generally strong in the run-up from $3, a couple of months ago to $4.50,” Stifel Nicolaus & Co analyst Annabel Samimy said.

Corcept is planning to submit a marketing approval application for its product Corlux, a potential Cushing’s Syndrome treatment, to U.S. regulators late in the first quarter of 2011 and would request for a priority review.

The hormone disorder, called Cushing’s syndrome, is caused by unusually high levels of cortisol -- a steroid hormone produced by the adrenal gland -- in blood.

Corcept plans to market Corlux in the United States independently and seek partnership to put it in markets abroad, the company said in a call with analysts.

Corlux was granted an orphan drug designation by the U.S. Food and Drug Administration (FDA), which would give the firm a seven-year marketing exclusivity in the U.S, upon approval.

In the United States, Corcept can bill up to $300 million in peak sales of Corlux, estimates Global Hunter Securities’ Kimberly Lee while Stifel Nicolaus’ Samimy sees peak sales of $230 million for the region by 2015.